WHITEBAIT, the vernacular name of the small fish which appears in large shoals in the estuary of the Thames during the summer months, and is held in great esteem as a delicacy for the table. Formerly whitebait was supposed to be a distinct species of fish. T. Pennant and G. Shaw believed it to be some kind of Cyprinoid, similar to the bleak, whilst E. Donovan, in his Natural History of British Fishes (1802-1808), misled by specimens sent to him as whitebait, declared it to be the young of the shad. In 1820 W. Yarrell proved conclusively that Donovan's opinion was founded on an error; unfortunately he contented himself with comparing whitebait with the shad only, and in the end adopted the opinion of the Thames fishermen, whose interest it was to represent it as a distinct adult form; thus the whitebait is introduced into Yarrell's History of British Fishes (1836) as Clupea alba. The French ichthyologist Valenciennes went a step farther, declaring it to be not only specifically but also generically distinct from all other Clupeoids. It is now known to consist of the young fry of herrings and sprats in varying proportions mixed with a few shrimps, gobies, sticklebacks, pope-fishes and young flounders; but these impurities are as far as possible picked out from the whitebait before it is marketed. The fishing is carried on from February to August, and samples taken in the successive months were found to contain the percentages of herrings, the remainder being young sprats: 7, 5, 14, 30, 87, 75, 52. Hence it will be seen that sprats predominated in February, March, April and May, herrings in June and July. There is reason to believe that these young herrings are derived from a local "winter" race spawning about February and March, and having nothing to do with the great shoals of the more open sea spawning in the North Sea in November. The Thames being unequal to the supply of the large demand for this delicacy, large quantities of whitebait are now brought to London and other markets from many parts of the coast. In times past whitebait were considered to be peculiar to the estuary of the Thames; and, even after the specific identification of Thames whitebait with the young of the herring and sprat, it was still thought that there was a distinctive superiority in its condition and flavour. It is possible that the young fish find in the estuary of the Thames a larger amount of suitable food than on other parts of the coast, where the water may be of greater purity, but possesses less abundance of the minute animal life on which whitebait thrive. Indeed, Thames whitebait which have been compared with that from the mouth of the Exe, the Cornish coast, Menai Strait, and the Firth of Forth seemed to be better fed; but, of course, the specific characteristics of the herring and the sprat—into which we need not enter here—were nowise modified.
The fry of fishes is used as an article of diet in almost every country: in Germany the young of various species of Cyprinoids, in Italy and Japan the young of nearly every fish capable of being readily captured in sufficient numbers, in the South Sea Islands the fry of Teuthis, in New Zealand young Galaxias are consumed in certain seasons in large quantities; and, like whitebait, these fry bear distinct names, different from those of the adult fish.
Whitebait are caught on the flood-tide from boats moored in from 3 to 5 fathoms. The net used is a bag some 20 ft. long, narrow and small-meshed towards the tail end, the mouth being kept open in the direction of the advancing tide by a framework 3 or 4 ft. square. It is placed alongside the boat and sunk to a depth of 4 ft. below the surface; from time to time the end of the bag is lifted into the boat, to empty it of its contents. The "schools" of whitebait advancing and retiring with the tide for days, and probably for weeks, have to run the gauntlet of a dozen of these nets, and therefore get very much thinned in number by the end of the season. When the view commenced to gain ground that the whitebait were largely young herring, the question arose whether or not the immense destruction of the young brood caused by this mode of fishing injuriously affected the fishery of the mature herring. This perhaps it does; but, since it has been ascertained that the herring is much more restricted in its migrations than were formerly believed, and that the shoals are to a great extent local, the injury, such as it is, must be local and limited to the particular district in which the fishing for whitebait is methodically practised. Similar reasoning applies to sprats.